Method for manufacturing rolling diaphragm devices



May 30, 1967 J. F. TAPLIN 3,321,823

METHOD FOR MANUFACTURING ROLLING DIAPHRAGM DEVICES Original Filed Jan.25, 1965 INV EN TOR.

United States Patent 3,321,823 METi-ltlll) FUR MANUFACTURHNG ROLLENGDiiAPHRAtG-M DEVli CES lohn F. Tapiin, l Sewail St, West Newton, Mass.02165 Original application Fan. 25, 1965, Ser. No. 427,847, now PatentNo. 3,233,670, dated Nov. 8, 1966. Divided and this application May 25,1966, Ser. No. 574,483 It Claim. (U. 29-1ss.4)

This is a division of my copending patent application filed Jan. 25,1965, Ser. No. 427,847,, now Patent No. 3,283,670 for Roiling DiaphragmDevices and Method for Manufacturing the Same.

This invention is concerned with, and relates to, a method of makingrolling diaphragm devices.

It is a general object of this invention to provide a method of makinggreatly improved rolling diaphragm devices.

Among the most important applications of rolling diaphragm devices rangefluid pumps and their mechanical reversal, i.e., fluid motors.

It is, therefore, another object of this invention to provide a methodof making greatly improved rolling diaphragm devices which lendthemselves for application as fluid pumps as well as fluid motors.

All prior art rolling diaphragm devices have a common drawback, orlimitation, consisting in that it had heretofore been practicallyimpossible to assure a perfect coaxial alignment of the rollingdiaphragm with the cylinder bore in the cylinder body of such devices.In other words, in none of the prior art devices is there an absolute,or even a Sufficient assurance that the rolling diaphragm is properlycentered in regard to the bore in the cylinder body with which therolling diaphragm is associated. Such misalignment results inmalfunctioning of rolling diaphragm devices, the degree ofmalfunctioning depending upon various factors. If the rolling diaphragmis but relatively slightly off center, the flex life of the rollingdiaphragm may be shortened, yet the device may function satisfactorilyfor a certain period of time. The reason responsible for the relativelyshort flex life of the rolling diaphragm may never be known. On theother hand, if a rolling dia phragm is badly misalinged, malfunctioningand serious trouble are likely to occur when, or shortly after, therolling diaphragm device is placed in service.

i It is, therefore, another object of this invention to provide a methodof making rolling diaphragm devices wherein centering of the rollingdiaphragm is achieved by positive means not subject to human errorrather than by the skill of the operator assembling the constituentparts of the rolling diaphragm device.

Another object of this invention is to provide a method making itpossible to readily manufacture and assemble the constituent parts ofimproved rolling diaphragm devices having positively precisely centeredrolling diaphragms.

Further objects and advantages of this invention will become apparent asthe following description proceeds, and the features of novelty whichcharacterize the invention will be pointed out with particularity in theclaims annexed to, and forming part of, this specification.

For a better understanding of the invention reference may be had to theaccompanying drawings in which:

FIG. 1 is a diagrammatic vertical section of a rolling diaphragm deviceembodying the present invention;

FIG. 2 shows a detail of FIG. 1 on a larger scale;

FIG. 3 is a diagrammatic vertical section of a mold used in making arolling diaphragm for the structure of FIGS. 1 and 2 and alsoillustrates a step in manufacturing said diaphragm; and

FIG. 4 is a diagrammatic vertical section through a trimming device orcutting device used in making a rolling diaphragm for the structure ofFIGS. 1 and 2 and also illustrates a step in manufacturing saiddiaphragm.

Referring now to the drawings, and more particularly to FIGS. 1 and 2thereof, numeral 1 has been applied to indicate the upper portion of acylinder body and numeral 2 has been applied to indicate the lowerportion of the cylinder body of a rolling diaphragm device. The upperportion 1 is provided with a screw threaded opening 1a and the lowerportion 2 is provided with a venting opening 2a. Piston 3 is arrangedinside of the cylindrical space defined by parts 1 and 2. There is a.gap between the lateral Wall of piston 3 and the bore in cylinder body1, 2 to receive the rolling wall of a rolling diaphgram. Piston rod 4slidable in bearing 5 integral with the lower portion 2 of the cylinderbody 1, 2 is fixedly connected to piston 3. Helical spring 6 rests withone end against the inner surface of the lower portion 2 of cylinderbody 1, 2 and with the otherend against piston 3 and biases piston 3 inupward direction. Reference character 7 has been applied to generallyindicate a rolling diaphragm, preferably made of a fabric reinforcedelastomer. The latter comprises radially outer annular flange 7a, arolling wall 7b forming a convolution, and a radially inner flange 7c.The latter is clamped between the end surface of piston 3 and a retainerplate 351 by means of a. screw 3b projecting transversely throughretainer plate 3a and piston 3 into piston rod 4. The lower portion 2 ofcylinder body 1, 2 is provided with an annular flange 2b, and theradially outer flange 7a of rolling diaphragm 7 rests upon annularflange 2b. Annular member or washer 8 rests upon the radially outerflange 7a of rolling diaphragm 7 and is firmly secured to the latter soas to form an integral part of the rolling diaphragm. Annular member orWasher 8.

is carefully and precisely centered in respect to rolling diaphragm 7,as will be explained below more in detail. The upper surface of annularmember or washer 8 is provided with a layer 9 of relatively soft rubber,or an equivalent elastomer. Flange 2b has an upstanding portion 20. Theradially inner cylindrical surface of upstanding flange portion 20 formsa centering surface for rolling diaphragm 7. To be more specific, theradially outer diameter of the edge portion of annular member or washer8 is exactly the same as the radially inner diameter of the upstand ngportion 2c forming a cooperating centering surface for the radiallyouter edge of part 8. As a result, the rolling diaphragm 7 is preciselycentered in regard to the cylindrical space defined by the two portions1 and 2 of cylinder body 1, 2, the radially inner surface of upstandingportion or centering ring 20 of flange 25 being precisely centered inregard to the cylindrical space defined by parts 1 and 2. The upperportion ll of cylinder body 1, 2 is provided with an annular flange 1bwhich rests upon the upper rubber layer 2 on annular member or washerii. The upstanding'portion or centering ring 20 forms a lip bent overthe upper surface of flange lb and clamping flange 1b against theannular stack or laminate formed by the radially outer flange of 7a ofrolling diaphragm 7, washer or annular member 8 and the rubber or otherelastomeric overlay 9 of the latter.

FIG. 1 shows the rolling diaphragm device in the neutral plane positionwhich is midway between the upstroke position and the downstrokeposition. The upstroke position is reached when piston 3 moves upwardlyunder the joint action of spring 6 and piston rod 4. During the upstrokeof piston 3 the portion of the rolling wall 712 of rolling diaphragm 7which had been in engagement with the wall of part 2 rolls off the wallof part 2 and unto the lateral wall of piston 3. In the upstrokeposition of piston 3 the entire rolling wall 7a of rolling diaphragm 7is in physical engagement with the lateral wall of piston 3. During theensuing downward stroke of piston 3 under the action of piston rod 4 andagainst the action of spring 6 the rolling wall 71) of rolling diaphragm7 rolls off the lateral wall of piston 3 unto the lateral wall ofportion 2 of cylinder body 1, 2. In the downstroke position of piston 3all of the rolling wall 71) of diaphragm 7 is transferred from piston 3unto the lateral wall portion of cylinder body 1, 2.

It will be understood that the presence of a centering ring adapted tocooperate, and cooperating, with the centering structure 8, 9 of rollingdiaphragm 7 is an essentail element of this invention. The centeringring does not necessarily need to be formed by the upstanding portion ofthe flange of the lower portion 2 of cylinder body 1, 2. It might beformed, for instance, by a separate annular part having a radially innerprojection resting against the upper surface of the flange integral withthe upper portion 1 of the cylinder body 1, 2 and having an internalscrew-thread cooperating with an external screwthread on the verticalradially outer edge portion of the flange integral with the lowerportion 2 of the cylinder body 1, 2. Such a ring is generally known asthreaded bezel ring. The radially outer surface of annular member orwasher 8 may be adapted to cooperate with the radially inner surface ofsuch a threaded bezel ring, thus properly centering the rollingdiaphragm in regard to the cylinder body 1, 2. In that particularinstance it is necessary to properly center the radially inner surfaceof the threaded bezel ring in regard to cylinder body 1, 2 to make itpossible for the radially inner surface of the bezel ring to operate ascentering surface for the rolling diaphragm.

The device shown in FIGS. 1 and 2 is predicated on maintaining coaxialrelation between the cylindrical centering surface on the upstandingportion 20 of flange 2b and the cylindrical bore in cylinder body 1, 2,and on maintaining coaxial relation between the rolling diaphragm 7 andthe annular member or washer 8. The first mentioned condition canreadily be met when manufacturing the cylinder body 1, 2. FIGS. 3 and 4illustrate how to meet the second mentioned condition.

In manufacturing rolling diaphragm devices according to the presentinvention substantially hat-shaped rolling diaphragms may be used asmore fully disclosed and claimed in U.S. Patent 2,849,026 to John F.Taplin. Such a substantially hat-shaped rolling diaphragm may be placedinto a conforming mold comprising the two mating mold portions 10 and11. The lower mold portion 10 includes an annular centering recess 10acoaxial to the hat-shaped portion of diaphragm 7 into which the radiallyouter flange portion 7a of diaphragm 7 is being fitted. Thereupon theelastomer-surfaced washer or reinforcement member 8 is fitted intocentering recess 10a. Washer 8 has exactly the same diameter ascentering recess 10a, thus perfectly fitting into the latter whenarranged coaxially to the hat-shaped portion of diaphragm 7. Thereuponmold 10, 11 is closed, and reinforcement member 8 and its elastomeroverlay 9 permanently aflixed to the radially outer flange portion ofrolling diaphragm 7. This operation may be achieved in different ways,preferably by the application of heat and pressure. Pressure is exertedupon flange 7a, washer 8 and its overlay 9 by a projection 11a formingpart of the upper mold portion 11. Washer 8 is made of a sheet materialhaving sufiicient dimensional stability to form at the edges thereof aprecise positioning abutment. Washer 8 may, for instance, be made of asuitable fiberreinforced synthetic resin. It may be permanently aflixedor laminated to flange 7b of diaphragm 7 by vulcanization, or by meansof a suitable adhesive. The tolerance between washer 8 and the centeringrecess 10a in mold 10, 11 into which flange 7b and washer 8 are fittedmay be in the order from .015" to .050". After the washer orreinforcement member 8 has been firmly afl'lxed or laminated to flange7b of diaphragm 7 the latter, including washer or reinforcement member8, is removed from mold 10, 11.

The next step consists in trimming the washer or reinforcement member8and the radially outer flange 7a of diaphragm 7to the right size, i.e.,to the size of the alignment surface on the alignment ring of therolling diaphragm device in combination with which the particularrolling diaphragm is intended to be used. This is achieved by means of atrimming device of which the left portion is diagrammatically shown inFIG. 4, the right portion being broken away in that figure since it isbeing identical to its left port-ion.

The trimming device shown in FIG. 4 comprises a lower portion or cuttingplate 13, and an upper portion or knife carrier 14. Cutting plate 13 isprovided with bores 13aof which but one is shown in FIG. 4engaged bydowel pins 14a. Cutting board 13 is further provided with a circularcentering recess 13b which is arranged in coaxial relation to a circularcutting knife 15 supportedby knife carrier 14. Bores 13a in cuttingplate 13 and dowels 14a in knife carrier 14 rigorously maintain thecoaxial relation of circular centering recess 13]) and of the circularcutting edge of the circular cutting knife 15. By moving knife carrier14 downwardly against the action of a biasing spring mechanism (notshown)-the laminate 7a, 8, 9 is trimmed to the exact circular sizerequired. Assuming it is desired to provide a rolling diaphragm for thestructure of FIGS. 1 and 2, this requires cutting the laminate 7a, 8, 9to the Size of the inner diameter of extension 2c of flange 2b of theportion 2 of cylinder body 1, 2. The trimmed diaphragm 7 is then removedfrom the trimming or cutting device shown in FIG. 4 and inserted intothe structure of FIGS. 1 and 2. In so doing physical engagement isestablished between the radially outer trimmed edge of laminate 7a, 8, 9and radially inner alignment surface of :part 20. Now rolling diaphragm7 is perfectly centered by abutting action and positively maintained inits centered position. Lip 2d may now be swaged to clamp annularlaminate 7a, 8, 9 in its position between flanges 1b and 211.

It will be understood that although but one embodiment of the inventionhas been shown and described in detail, the invention is not limitedthereto, and that the illustrated embodiment may be modified, or otherembodiments made, without departing from the spirit and scope of theinvention as set forth in the accompanying claim.

I claim as my invention:

A method for manufacturing rolling diaphragm devices including analignment ring having a cylindrical alignment surface of predeterminedinner diameter being arranged in coaxial relation to the bore in thecylinder body of the rolling diaphragm device, said method including thesteps of:

(a) placing a substantially hat-shaped rolling diaphrag of a fabricreinforced elastomer into a conforming mold and fitting a radially outerflange of said rolling diaphragm into a circular centering recessdefined by said mold;

(b) superimposingv upon said radially outer flange of said rollingdiaphragm while in said mold an elastomer-surfaced annular reinforcementmember having the same diameter as said centering recess defined by saidmold, simultaneously fitting said reinforcement member into saidcentering recess of said mold, and thereafter permanently aflixing saidreinforcement member to said flange of said rolling diaphragm while saidrolling diaphragm still is in said mold;

(c) removing said rolling diaphragm from said mold with saidreinforcement member permanently affixed to said radially outer flangeof said rolling diaphragm, fitting said reinforcement member into acircular centering recess of a trimming device, and thereafter trimmingsaid reinforcement member to the exact diameter of said alignmentsurface on said alignment ring; and

(d) establishing thereafter physical engagement between the radiallyouter trimmed edge of said reinforcement member and said alignmentsurface on said alignment ring.

References Cited UNITED STATES PATENTS Kuen 29-445 Foehr 156-267 XMcCormack 29-481 Hornbostel 92-103 Barr 29-1564 X Gold et a1. 92-103 X10 CHARLIE T. MOON, Primary Examiner.

